In testing the threaded connections between sections of pipe for leaks, it is common practice to insert into the bore of the pipe a test tool having a body member with spaced packers thereon that straddle the joint to be tested. After the packers have been expanded, fluid pressure is applied to the annular region between the packers adjacent the threaded joint to determine if the same is leakproof. When a test tool of the type described is used to test a threaded joint between two sections of pipe having different internal diameters, for example where the two sections have differing weights and wall thicknesses, or where two different size pipes are joined together by an adaptor sub, a significant problem arises. The difference in transverse cross-sectional areas sealed off by the packer elements creates a piston effect so that the pressure of the test fluid tends to blow the test tool out of the pipe. Such an occurrence can be extremely dangerous to personnel operating the equipment, and results in serious damage to the equipment itself.
It is the general object of the present invention to provide a new and improved test tool of the type described that includes means to anchor the tool against movement in the pipe even when the packer elements are sealed against different internal pipe section diameters during a testing operation.